Invention relates to disk drive electronics, particularly to reduction of electromigration (EM) effect on magneto-resistive (MR) drive media.
Conventional disk drives, especially so-called MR drives, are sometimes produced having increased head resistance to generate higher amplitude for output signals, and, thus, result in overall improved performance and yield. However, high-resistance heads lead to increased EM effect, which results in undesirable field failure over time. Accordingly, such undesirable EM effect caused by high resistance poses a significant challenge to designing and producing high-end drives, having high recording density and higher spindle speeds, and requiring improved head performance at higher drive operating temperatures. In particular, high spindle speed is associated with relatively higher drive operating and head temperatures.
There is a need, therefore, for improved solution to provide high-performance drives, but without substantially contributing to undesirable EM effects.
Invention resides in system and/or method associated with disk drive to indicate one or more heads having a range of resistance values for performing specified operation during designated operational mode(s). For example, in multi-MR head system, such head measured to have lowest resistance is selected to perform track-servo operation during sleep or quiescent mode. Hence, in this selective operational manner, EM lifetime for such drive system is substantially prolonged.